Most fiber-coupled laser (Light Amplification by Stimulated Emission of Radiation) diode pumps have been developed for large volume industrial applications where the primary metrics are price-per-bright-watts and reliability. In conventional high-power fiber laser technology a significant portion of the weight and volume of the total fiber laser system is in the high powered diode pumps where much of the weight and volume is devoted to waste heat removal. For example, high-powered laser diode pumps are commonly cooled with chilling plates made of highly thermally conductive material such as copper (Cu). This adds significant excess mass and volume to a laser system.
In mobile laser applications the key metrics also include volume, weight, and electrical-to-optical power conversion efficiency (PCE). Industrial diode lasers typically weigh more than 1 kg/kW (kilograms/kilowatt) of power output, and have volumes that are greater than twice what would be acceptable for mobile High Energy Laser (TEEL) applications. Furthermore, industrial diode lasers typically have a PCE of approximately 50% whereas mobile HEL applications require a PCE above 55%. So there is a need for laser diode pumps that are optimized for size, weight, and power efficiency (SWAP) in addition to price-per-bright-watts and reliability.
Directed (laser) energy continues to offer promise as the Department of Defense (DOD) encounters new asymmetric and disruptive threats as well as increasingly sophisticated traditional challenges. Recent advances in electrically-based solid-state and, especially, optical fiber lasers have shown improved power levels and efficiency, paving the way towards deployable >100 kW class high energy lasers. However, for many DoD applications, size, weight and power (SWAP) consumption are still too large.